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Mukhopadhyay A, Paulino V, Liu K, Donley CL, Bernard B, Shomar A, Liu C, Olivier JH. Leveraging the Assembly of a Rylene Dye to Tune the Semiconducting Properties of Functionalized n-Type, Hybrid Si Interfaces. ACS APPLIED MATERIALS & INTERFACES 2021; 13:4665-4675. [PMID: 33443396 DOI: 10.1021/acsami.0c18222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The functionalization of silicon electrodes with π-conjugated chromophores opens new avenues to engineer hybrid semiconducting interfaces relevant to information storage and processing. Notably, molecularly dissolved π-conjugated units, such as ferrocene derivatives, are traditionally exploited as building blocks to construct well-defined interfaces that establish electrochemically addressable platforms with which to investigate electron transfer properties and charge storage capabilities. In contrast, planar π-conjugated building blocks such as naphthalene diimide (NDI) cores enable the formation of solvated aggregates equipped with emergent electronic structures not manifested by the parent, molecularly dissolved building blocks. To interrogate the extent to which the aggregated states of π-conjugated chromophores can be leveraged to regulate the n-type semiconducting properties of functionalized electrodes, we have devised an amphiphilic rylene core (NDI) that demonstrates a non-negligible degree of aggregation in an aqueous medium. Characterization of the electronic structures of the NDI-derived aggregates using a combination of electrochemistry, reductive titration experiments, and spectroelectrochemistry unveils the existence of π-anion stacks, the formation of which is contingent on the initial concentration of NDI building blocks. We show that grafting n-doped NDI aggregates on silicon electrode precursors equipped with a high density of anchoring groups by means of "click" reaction enables the formation of the hybrid Si-NDI electrode (Si-NDI-15@1) that facilitates electron injection by more than 400 mV when compared to Si interfaces constructed from molecularly dissolved NDI units. Furthermore, the engineering of a Si precursor surface characterized by a low density of anchoring groups provides additional proof to highlight that the potentiometric properties recorded for Si-NDI-15@1 originate from NDI units, evidencing a non-negligible degree of aggregation. The present work delivers tools to manipulate the potentiometric properties of functionalized electrodes by leveraging on the electronic structures of aggregated, π-conjugated precursors.
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Affiliation(s)
- Arindam Mukhopadhyay
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Victor Paulino
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Kaixuan Liu
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Carrie L Donley
- Chapel Hill Analytical and Nanofabrication Laboratory, Department of Applied Physical Sciences, University of North Carolina, 243 Chapman Hall, Chapel Hill, North Carolina 27599, United States
| | - Brianna Bernard
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Alfred Shomar
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Chuan Liu
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Jean-Hubert Olivier
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
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2
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Yang Y, Mansfeld FM, Kavallaris M, Gaus K, Tilley RD, Gooding JJ. Monitoring the heterogeneity in single cell responses to drugs using electrochemical impedance and electrochemical noise. Chem Sci 2020; 12:2558-2566. [PMID: 34164023 PMCID: PMC8179273 DOI: 10.1039/d0sc05489e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 12/28/2020] [Indexed: 12/24/2022] Open
Abstract
Impedance spectroscopy is a widely used technique for monitoring cell-surface interactions and morphological changes, typically based on averaged signals from thousands of cells. However, acquiring impedance data at the single cell level, can potentially reveal cell-to-cell heterogeneity for example in response to chemotherapeutic agents such as doxorubicin. Here, we present a generic platform where light is used to define and localize the electroactive area, thus enabling the impedance measurements for selected single cells. We firstly tested the platform to assess phenotypic changes in breast cancer cells, at the single cell level, using the change in the cell impedance. We next show that changes in electrochemical noise reflects instantaneous responses of the cells to drugs, prior to any phenotypical changes. We used doxorubicin and monensin as model drugs and found that both drug influx and efflux events affect the impedance noise signals. Finally, we show how the electrochemical noise signal can be combined with fluorescence microscopy, to show that the noise provides information on cell susceptibility and resistance to drugs at the single cell level. Together the combination of electrochemical impedance and electrochemical noise with fluorescence microscopy provides a unique approach to understanding the heterogeneity in the response of single cells to stimuli where there is not phenotypic change.
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Affiliation(s)
- Ying Yang
- School of Chemistry, The University of New South Wales Sydney NSW 2052 Australia
- Australian Centre for NanoMedicine, The University of New South Wales Sydney NSW 2052 Australia
- The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales Sydney NSW 2052 Australia
| | - Friederike M Mansfeld
- Australian Centre for NanoMedicine, The University of New South Wales Sydney NSW 2052 Australia
- The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales Sydney NSW 2052 Australia
- Children's Cancer Institute, The University of New South Wales Sydney NSW 2052 Australia
- Monash Institute of Pharmaceutical Sciences, Monash University Melbourne VIC 3052 Australia
| | - Maria Kavallaris
- Australian Centre for NanoMedicine, The University of New South Wales Sydney NSW 2052 Australia
- The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales Sydney NSW 2052 Australia
- Children's Cancer Institute, The University of New South Wales Sydney NSW 2052 Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, The University of New South Wales Sydney NSW 2052 Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, The University of New South Wales Sydney NSW 2052 Australia
| | - Richard D Tilley
- School of Chemistry, The University of New South Wales Sydney NSW 2052 Australia
- Australian Centre for NanoMedicine, The University of New South Wales Sydney NSW 2052 Australia
| | - J Justin Gooding
- School of Chemistry, The University of New South Wales Sydney NSW 2052 Australia
- Australian Centre for NanoMedicine, The University of New South Wales Sydney NSW 2052 Australia
- The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales Sydney NSW 2052 Australia
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3
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Chen J, Hu G, Li T, Chen Y, Gao M, Li Q, Hao L, Jia Y, Wang L, Wang Y. Fusion peptide engineered "statically-versatile" titanium implant simultaneously enhancing anti-infection, vascularization and osseointegration. Biomaterials 2020; 264:120446. [PMID: 33069134 DOI: 10.1016/j.biomaterials.2020.120446] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 12/12/2022]
Abstract
Although antimicrobial titanium implants can prevent biomaterial-associated infection (BAI) in orthopedics, they display cytotoxicity and delayed osseointegration. Therefore, versatile implants are desirable for simultaneously inhibiting BAI and promoting osseointegration, especially "statically-versatile" ones with nonessential external stimulations for facilitating applications. Herein, we develop a "statically-versatile" titanium implant by immobilizing an innovative fusion peptide (FP) containing HHC36 antimicrobial sequence and QK angiogenic sequence via sodium borohydride reduction promoted Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC-SB), which shows higher immobilization efficiency than traditional CuAAC with sodium ascorbate reduction (CuAAC-SA). The FP-engineered implant exhibits over 96.8% antimicrobial activity against four types of clinical bacteria (S. aureus, E. coli, P. aeruginosa and methicillin-resistant S. aureus), being stronger than that modified with mixed peptides. This can be mechanistically attributed to the larger bacterial accessible surface area of HHC36 sequence. Notably, the implant can simultaneously enhance cellular proliferation, up-regulate expressions of angiogenesis-related genes/proteins (VEGF and VEGFR-2) of HUVECs and osteogenesis-related genes/proteins (ALP, COL-1, RUNX-2, OPN and OCN) of hBMSCs. In vivo assay with infection and non-infection bone-defect model reveals that the FP-engineered implant can kill 99.63% of S. aureus, and simultaneously promote vascularization and osseointegration. It is believed that this study presents an excellent strategy for developing "statically-versatile" orthopedic implants.
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Affiliation(s)
- Junjian Chen
- Key Laboratory of Biomedical Engineering of Guangdong Province, South China University of Technology, Guangzhou, 510006, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510006, China
| | - Guansong Hu
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou, 510006, China; School of Biomedical Science and Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Tianjie Li
- Key Laboratory of Biomedical Engineering of Guangdong Province, South China University of Technology, Guangzhou, 510006, China
| | - Yunhua Chen
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou, 510006, China
| | - Meng Gao
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou, 510006, China; School of Biomedical Science and Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Qingtao Li
- Key Laboratory of Biomedical Engineering of Guangdong Province, South China University of Technology, Guangzhou, 510006, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510006, China
| | - Lijing Hao
- School of Biomedical Science and Engineering, South China University of Technology, Guangzhou, 510006, China; Key Laboratory of Biomedical Engineering of Guangdong Province, South China University of Technology, Guangzhou, 510006, China
| | - Yongguang Jia
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou, 510006, China
| | - Lin Wang
- Key Laboratory of Biomedical Engineering of Guangdong Province, South China University of Technology, Guangzhou, 510006, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510006, China.
| | - Yingjun Wang
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou, 510006, China; School of Biomedical Science and Engineering, South China University of Technology, Guangzhou, 510006, China.
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4
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Mukhopadhyay A, Bernard B, Liu K, Paulino V, Liu C, Donley C, Olivier JH. Molecular Strategies to Modulate the Electrochemical Properties of P-Type Si(111) Surfaces Covalently Functionalized with Ferrocene and Naphthalene Diimide. J Phys Chem B 2019; 123:11026-11041. [DOI: 10.1021/acs.jpcb.9b09812] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Arindam Mukhopadhyay
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Brianna Bernard
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Kaixuan Liu
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Victor Paulino
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Chuan Liu
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Carrie Donley
- Chapel Hill Analytical and Nanofabrication Laboratory, Department of Applied Physical Sciences, University of North Carolina, 243 Chapman Hall, Chapel Hill, North Carolina 27599, United States
| | - Jean-Hubert Olivier
- Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
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5
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Lian J, Yang Y, Wang W, Parker SG, Gonçales VR, Tilley RD, Gooding JJ. Amorphous silicon on indium tin oxide: a transparent electrode for simultaneous light activated electrochemistry and optical microscopy. Chem Commun (Camb) 2018; 55:123-126. [PMID: 30516184 DOI: 10.1039/c8cc07889k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Herein is reported a new type of transparent electrode, prepared by depositing a thin layer of amorphous silicon film on indium tin oxide, which enables photoswitchable electrochemistry and optical imaging to be performed simultaneously. This offers the opportunity to visualise a spatially controlled electrochemical event on an unstructured electrode surface.
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Affiliation(s)
- Jiaxin Lian
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia.
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6
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Zarei L, Tavallaie R, Choudhury MH, Parker SG, Bakthavathsalam P, Ciampi S, Gonçales VR, Gooding JJ. DNA-Hybridization Detection on Si(100) Surfaces Using Light-Activated Electrochemistry: A Comparative Study between Bovine Serum Albumin and Hexaethylene Glycol as Antifouling Layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14817-14824. [PMID: 30185042 DOI: 10.1021/acs.langmuir.8b02222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Light can be used to spatially resolve electrochemical measurements on a semiconductor electrode. This phenomenon has been explored to detect DNA hybridization with light-addressable potentiometric sensors and, more recently, with light-addressable amperometric sensors based on organic-monolayer-protected Si(100). Here, a contribution to the field is presented by comparing sensing performances when bovine serum albumin (BSA) and hexaethylene glycol (OEG6) are employed as antifouling layers that resist nonspecific adsorption to the DNA-modified interface on Si(100) devices. What is observed is that both sensors based on BSA or OEG6 initially allow electrochemical distinction among complementary, noncomplementary, and mismatched DNA targets. However, only surfaces based on OEG6 can sustain electroactivity over time. Our results suggest that this relates to accelerated SiO x formation occasioned by BSA proteins adsorbing on monolayer-protected Si(100) surfaces. Therefore, DNA biosensors were analytically explored on low-doped Si(100) electrodes modified on the molecular level with OEG6 as an antifouling layer. First, light-activated electrochemical responses were recorded over a range of complementary DNA target concentrations. A linear semilog relation was obtained from 1.0 × 10-11 to 1.0 × 10-6 mol L-1 with a correlation coefficient of 0.942. Then, measurements with three independent surfaces indicated a relative standard deviation of 4.5%. Finally, selectivity tests were successfully performed in complex samples consisting of a cocktail mixture of four different DNA sequences. Together, these results indicate that reliable and stable light-activated amperometric DNA sensors can be achieved on Si(100) by employing OEG6 as an antifouling layer.
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Affiliation(s)
- Leila Zarei
- School of Chemistry, Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Roya Tavallaie
- School of Chemistry, Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Moinul H Choudhury
- School of Chemistry, Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Stephen G Parker
- School of Chemistry, Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Padmavathy Bakthavathsalam
- School of Chemistry, Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Simone Ciampi
- Department of Chemistry , Curtin University , Bentley , Western Australia 6102 , Australia
| | - Vinicius R Gonçales
- School of Chemistry, Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - J Justin Gooding
- School of Chemistry, Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , New South Wales 2052 , Australia
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7
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Veerbeek J, Méndez‐Ardoy A, Huskens J. Electrochemistry of Redox-Active Guest Molecules at β-Cyclodextrin-Functionalized Silicon Electrodes. ChemElectroChem 2017; 4:1470-1477. [PMID: 28706776 PMCID: PMC5485161 DOI: 10.1002/celc.201600872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Indexed: 11/08/2022]
Abstract
Functionalization of silicon-based sensing devices with self-assembled receptor monolayers offers flexibility and specificity towards the requested analyte as well as the possibility of sensor reuse. As electrical sensor performance is determined by electron transfer, we functionalized H-terminated silicon substrates with β-cyclodextrin (β-CD) molecules to investigate the electronic coupling between these host monolayers and the substrate. A trivalent (one ferrocene and two adamantyl moieties), redox-active guest was bound to the β-CD surface with a coverage of about 10-11 mol/cm2 and an overall binding constant of 1.5⋅109 M-1. This packing density of the host monolayers on silicon is lower than that for similar β-CD monolayers on gold. The monolayers were comparable on low-doped p-type and highly doped p++ substrates regarding their packing density and the extent of oxide formation. Nonetheless, the electron transfer was more favorable on p++ substrates, as shown by the lower values of the peak splitting and peak widths in the cyclic voltammograms. These results show that the electron-transfer rate on the host monolayers is not only determined by the composition of the monolayer, but also by the doping level of the substrate.
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Affiliation(s)
- Janneke Veerbeek
- Molecular NanoFabrication GroupMESA+ Institute for Nanotechnology, University of TwenteP.O. Box 2177500 AEEnschedeThe Netherlands
| | - Alejandro Méndez‐Ardoy
- Molecular NanoFabrication GroupMESA+ Institute for Nanotechnology, University of TwenteP.O. Box 2177500 AEEnschedeThe Netherlands
| | - Jurriaan Huskens
- Molecular NanoFabrication GroupMESA+ Institute for Nanotechnology, University of TwenteP.O. Box 2177500 AEEnschedeThe Netherlands
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8
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Wu F, Zhang DW, Wang J, Watkinson M, Krause S. Copper Contamination of Self-Assembled Organic Monolayer Modified Silicon Surfaces Following a "Click" Reaction Characterized with LAPS and SPIM. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:3170-3177. [PMID: 28285531 DOI: 10.1021/acs.langmuir.6b03831] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) reaction combined with microcontact printing was used successfully to pattern alkyne-terminated self-assembled organic monolayer-modified silicon surfaces. Despite the absence of a copper peak in X-ray photoelectron spectra, copper contamination was found and visualized using light-addressable potentiometric sensors (LAPS) and scanning photo-induced impedance microscopy (SPIM) after the "click"-modified silicon surfaces were rinsed with hydrochloric acid (HCl) solution, which was frequently used to remove copper residues in the past. Even cleaning with an ethylenediaminetetraacetic acid (EDTA) solution did not remove the copper residue completely. Different strategies for avoiding copper contamination, including the use of bulky chelators for the copper(I) catalyst and rinsing with different reagents, were tested. Only cleaning of the silicon surfaces with an EDTA solution containing trifluoroacetic acid (TFA) after the click modification proved to be an effective method as confirmed by LAPS and SPIM results, which showed the expected potential shift due to the surface charge introduced by functional groups in the monolayer and allowed, for the first time, imaging the impedance of an organic monolayer.
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Affiliation(s)
| | - De-Wen Zhang
- Institute of Materials, China Academy of Engineering Physics , Jiangyou 621908, Sichuan, P.R. China
| | - Jian Wang
- Institute of Medical Engineering, School of Basic Medical Science, Xi'an Jiaotong University Health Science Center , Xi'an 710061, P.R. China
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9
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Yang Y, Ciampi S, Gooding JJ. Coupled Thermodynamic and Kinetic Changes in the Electrochemistry of Ferrocenyl Monolayers Induced by Light. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2497-2503. [PMID: 28212037 DOI: 10.1021/acs.langmuir.6b04106] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on the light-induced systematic changes to the thermodynamics and kinetics of ferrocene units attached to a n-type silicon(100) photoelectrode. Both the reaction rate and the energetics of the charge transfer are simultaneously affected by changes in the intensity of the incident light. Cyclic voltammetry shows that increases in the intensity of illumination can drive the redox process toward less positive potentials, with a downhill shift in E1/2 of ca. 160 mV by increasing the light intensity from 3 to 94 mW cm-2. However, this thermodynamic shift is paralleled by an increase in the kinetics of the charge transfer. This latter observation-light-induced kinetic effects at monolayers on silicon electrodes-is made possible only by the stability of the surface chemistry construct. Furthermore, electrochemical impedance measurements showed that the electrodes exhibit faster electron-transfer kinetics under illumination than previously reported for ferrocene-terminated highly doped silicon (around 1 order of magnitude faster). An explanation for the kinetic effects is proposed on the basis of the consistent increase in photogenerated charge carriers inside silicon and the enlarged potential difference between the valence band of silicon and the surface-attached ferrocene.
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Affiliation(s)
- Ying Yang
- School of Chemistry, The University of New South Wales , Sydney NSW 2052, Australia
| | - Simone Ciampi
- Department of Chemistry, Curtin University , Bentley WA 6102, Australia
| | - J Justin Gooding
- School of Chemistry, The University of New South Wales , Sydney NSW 2052, Australia
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10
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Gebala M, La Mantia F, Michaels PE, Ciampi S, Gupta B, Parker SG, Tavallaie R, Gooding JJ. Electric Field Modulation of Silicon upon Tethering of Highly Charged Nucleic Acids. Capacitive Studies on DNA‐modified Silicon (111). ELECTROANAL 2016. [DOI: 10.1002/elan.201600285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Magdalena Gebala
- Analytische Chemie – Elektroanalytik & Sensorik, Ruhr-Universität Bochum Universitätsstr.150 D-44780 Bochum Germany
- Department of Biochemistry Stanford University Stanford CA 94305 USA
| | - Fabio La Mantia
- Energiespeicher- und Energiewandlersysteme Universität Bremen Wiener Str. 12 D-28359 Bremen Germany
| | - Pauline Eugene Michaels
- School of Chemistry and the Australian Centre for NanoMedicine The University of New South Wales Sydney NSW 2052 Australia
| | - Simone Ciampi
- School of Chemistry and the Australian Centre for NanoMedicine The University of New South Wales Sydney NSW 2052 Australia
| | - Bakul Gupta
- School of Chemistry and the Australian Centre for NanoMedicine The University of New South Wales Sydney NSW 2052 Australia
| | - Stephen G. Parker
- School of Chemistry and the Australian Centre for NanoMedicine The University of New South Wales Sydney NSW 2052 Australia
| | - Roya Tavallaie
- School of Chemistry and the Australian Centre for NanoMedicine The University of New South Wales Sydney NSW 2052 Australia
| | - J. Justin Gooding
- School of Chemistry and the Australian Centre for NanoMedicine The University of New South Wales Sydney NSW 2052 Australia
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11
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Kashi MB, Wu Y, Gonçales VR, Choudhury MH, Ciampi S, Gooding JJ. Silicon–SAM–AuNP electrodes: Electrochemical “switching” and stability. Electrochem commun 2016. [DOI: 10.1016/j.elecom.2016.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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12
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Zhang L, Vogel YB, Noble BB, Gonçales VR, Darwish N, Brun AL, Gooding JJ, Wallace GG, Coote ML, Ciampi S. TEMPO Monolayers on Si(100) Electrodes: Electrostatic Effects by the Electrolyte and Semiconductor Space-Charge on the Electroactivity of a Persistent Radical. J Am Chem Soc 2016; 138:9611-9. [PMID: 27373457 DOI: 10.1021/jacs.6b04788] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work demonstrates the effect of electrostatic interactions on the electroactivity of a persistent organic free radical. This was achieved by chemisorption of molecules of 4-azido-2,2,6,6-tetramethyl-1-piperdinyloxy (4-azido-TEMPO) onto monolayer-modified Si(100) electrodes using a two-step chemical procedure to preserve the open-shell state and hence the electroactivity of the nitroxide radical. Kinetic and thermodynamic parameters for the surface electrochemical reaction are investigated experimentally and analyzed with the aid of electrochemical digital simulations and quantum-chemical calculations of a theoretical model of the tethered TEMPO system. Interactions between the electrolyte anions and the TEMPO grafted on highly doped, i.e., metallic, electrodes can be tuned to predictably manipulate the oxidizing power of surface nitroxide/oxoammonium redox couple, hence showing the practical importance of the electrostatics on the electrolyte side of the radical monolayer. Conversely, for monolayers prepared on the poorly doped electrodes, the electrostatic interactions between the tethered TEMPO units and the semiconductor-side, i.e., space-charge, become dominant and result in drastic kinetic changes to the electroactivity of the radical monolayer as well as electrochemical nonidealities that can be explained as an increase in the self-interaction "a" parameter that leads to the Frumkin isotherm.
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Affiliation(s)
- Long Zhang
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong , Wollongong, New South Wales 2500, Australia
| | - Yan Boris Vogel
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong , Wollongong, New South Wales 2500, Australia
| | - Benjamin B Noble
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University , Canberra, Australian Capital Territory 2601, Australia
| | - Vinicius R Gonçales
- School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence for Convergent Bio-Nano Science and Technology, The University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Nadim Darwish
- Institut de Bioenginyeria de Catalunya (IBEC) , Baldiri Reixac 15-21, Barcelona 08028, Catalonia Spain
| | - Anton Le Brun
- Bragg Institute, Australian Nuclear Science and Technology Organisation (ANSTO) , Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - J Justin Gooding
- School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence for Convergent Bio-Nano Science and Technology, The University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Gordon G Wallace
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong , Wollongong, New South Wales 2500, Australia
| | - Michelle L Coote
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University , Canberra, Australian Capital Territory 2601, Australia
| | - Simone Ciampi
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong , Wollongong, New South Wales 2500, Australia
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Affiliation(s)
- Bruno Fabre
- Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS/Université de Rennes 1, Matière Condensée et Systèmes Electroactifs MaCSE, 35042 Rennes Cedex, France
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14
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Jiang C, Alam MT, Parker SG, Darwish N, Gooding JJ. Strategies To Achieve Control over the Surface Ratio of Two Different Components on Modified Electrodes Using Aryldiazonium Salts. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2509-17. [PMID: 26901641 DOI: 10.1021/acs.langmuir.5b04550] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Controlling the composition of an interface is very important in tuning the chemical and physical properties of a surface in many applications including biosensors, biomaterials, and chemical catalysis. Frequently, this requires one molecular component to a minor component in a mixed layer. Such subtle control of composition has been difficult to achieve using aryldiazonium salts. Herein, aryldiazonium salts of carboxyphenyl (CP) and phenylphosphorylcholine (PPC), generated in situ from their corresponding anilines, are electrografted to form molecular platform that are available for further functionalization. These two components are chosen because CP provides a convenient functionality for further coupling of biorecognition species while PPC offers resistance to nonspecific adsorption of proteins to the surface. Mixed layers of CP and PPC were prepared by grafting them either simultaneously or consecutively. The latter strategy allows an interface to be developed in a controlled way where one component is at levels of less than 1% of the total layer.
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Affiliation(s)
- Cheng Jiang
- School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales , Sydney, NSW 2052, Australia
| | - Muhammad Tanzirul Alam
- School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales , Sydney, NSW 2052, Australia
| | - Stephen G Parker
- School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales , Sydney, NSW 2052, Australia
| | - Nadim Darwish
- School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales , Sydney, NSW 2052, Australia
| | - J Justin Gooding
- School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales , Sydney, NSW 2052, Australia
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15
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Mohammadi Ziarani G, Hassanzadeh Z, Gholamzadeh P, Asadi S, Badiei A. Advances in click chemistry for silica-based material construction. RSC Adv 2016. [DOI: 10.1039/c5ra26034e] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Click chemistry is undoubtedly the most powerful 1,3-dipolar cycloaddition reaction in organic synthesis.
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Affiliation(s)
| | | | | | - Shima Asadi
- Department of Chemistry
- Alzahra University
- Tehran
- Iran
| | - Alireza Badiei
- School of Chemistry
- College of Science
- University of Tehran
- Tehran
- Iran
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16
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The impact of surface coverage on the kinetics of electron transfer through redox monolayers on a silicon electrode surface. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.10.125] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Choudhury MH, Ciampi S, Yang Y, Tavallaie R, Zhu Y, Zarei L, Gonçales VR, Gooding JJ. Connecting electrodes with light: one wire, many electrodes. Chem Sci 2015; 6:6769-6776. [PMID: 28757968 PMCID: PMC5508692 DOI: 10.1039/c5sc03011k] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 08/28/2015] [Indexed: 11/21/2022] Open
Abstract
The requirement of a wire to each electrode is central to the design of any electronic device but can also be a major restriction. For example it entails space restrictions and rigid device architecture in multi-electrode devices. The finite space that is taken up by the array of electrical terminals and conductive pads also severely limits the achievable density of electrodes in the device. Here it is shown that a travelling light pointer can be used to form transient electrical connections anywhere on a monolithic semiconductor electrode that is fitted with a single peripheral electrical terminal. This is achieved using hydrogen terminated silicon electrodes that are modified with well-defined organic monolayers. It is shown that electrochemical information can be either read from or written onto these surfaces. Using this concept it is possible to form devices that are equivalent to a conventional electrode array but that do not require a predetermined architecture, and where each element of the array is temporally "connected" using light stimulus; a step change in capability for electrochemistry.
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Affiliation(s)
- Moinul H Choudhury
- School of Chemistry , The University of New South Wales , Sydney , NSW 2052 , Australia .
| | - Simone Ciampi
- School of Chemistry , The University of New South Wales , Sydney , NSW 2052 , Australia .
| | - Ying Yang
- School of Chemistry , The University of New South Wales , Sydney , NSW 2052 , Australia .
| | - Roya Tavallaie
- School of Chemistry , The University of New South Wales , Sydney , NSW 2052 , Australia .
- Australian Centre for NanoMedicine , The University of New South Wales , Sydney , NSW 2052 , Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , NSW 2052 , Australia
| | - Ying Zhu
- School of Chemistry , The University of New South Wales , Sydney , NSW 2052 , Australia .
| | - Leila Zarei
- School of Chemistry , The University of New South Wales , Sydney , NSW 2052 , Australia .
| | - Vinicius R Gonçales
- School of Chemistry , The University of New South Wales , Sydney , NSW 2052 , Australia .
| | - J Justin Gooding
- School of Chemistry , The University of New South Wales , Sydney , NSW 2052 , Australia .
- Australian Centre for NanoMedicine , The University of New South Wales , Sydney , NSW 2052 , Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , The University of New South Wales , Sydney , NSW 2052 , Australia
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18
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Wang J, Wu F, Watkinson M, Zhu J, Krause S. "Click" Patterning of Self-Assembled Monolayers on Hydrogen-Terminated Silicon Surfaces and Their Characterization Using Light-Addressable Potentiometric Sensors. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:9646-9654. [PMID: 26274063 DOI: 10.1021/acs.langmuir.5b02069] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Two potential strategies for chemically patterning alkyne-terminated self-assembled monolayers (SAMs) on oxide-free silicon or silicon-on-sapphire (SOS) substrates were investigated and compared. The patterned surfaces were validated using a light-addressable potentiometric sensor (LAPS) for the first time. The first strategy involved an integration of photolithography with "click" chemistry. Detailed surface characterization (i.e. water contact angle, ellipsometry, AFM, and XPS) and LAPS measurements showed that photoresist processing not only decreases the coverage of organic monolayers but also introduces chemically bonded contaminants on the surfaces, thus significantly reducing the quality of the SAMs and the utility of "click" surface modification. The formation of chemical contaminants in photolithography was also observed on carboxylic acid- and alkyl-terminated monolayers using LAPS. In contrast, a second approach combined microcontact printing (μCP) with "click" chemistry; that is azide (azido-oligo(ethylene glycol) (OEG)-NH2) inks were printed on alkyne-terminated SAMs on silicon or SOS through PDMS stamps. The surface characterization results for the sample printed with a flat featureless PDMS stamp demonstrated a nondestructive and efficient method of μCP to perform "click" reactions on alkyne-terminated, oxide-free silicon surfaces for the first time. For the sample printed with a featured PDMS stamp, LAPS imaging showed a good agreement with the pattern of the PDMS stamp, indicating the successful chemical patterning on non-oxidized silicon and SOS substrates and the capability of LAPS to image the molecular patterns with high sensitivity.
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Affiliation(s)
- Jian Wang
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
| | - Fan Wu
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
| | - Michael Watkinson
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
| | - Jingyuan Zhu
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
| | - Steffi Krause
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
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19
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Michaels P, Alam MT, Ciampi S, Rouesnel W, Parker SG, Choudhury MH, Gooding JJ. A robust DNA interface on a silicon electrode. Chem Commun (Camb) 2014; 50:7878-80. [DOI: 10.1039/c4cc03418j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Schematic of a DNA sensing interface formed on oxide-free silicon electrodes that both resist nonspecific adsorption of DNA and maintains stable electrical properties in biological media.
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Affiliation(s)
- Pauline Michaels
- School of Chemistry
- The University of New South Wales
- Sydney, Australia
| | | | - Simone Ciampi
- School of Chemistry
- The University of New South Wales
- Sydney, Australia
| | - William Rouesnel
- School of Chemistry
- The University of New South Wales
- Sydney, Australia
| | - Stephen G. Parker
- School of Chemistry
- The University of New South Wales
- Sydney, Australia
- Australian Centre for NanoMedicine
- The University of New South Wales
| | | | - J. Justin Gooding
- School of Chemistry
- The University of New South Wales
- Sydney, Australia
- Australian Centre for NanoMedicine
- The University of New South Wales
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20
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Daschner de Tercero M, Gonzáles Martínez I, Herrmann M, Bruns M, Kübel C, Jennewein S, Fehrenbacher U, Barner L, Türk M. Synthesis of in situ functionalized iron oxide nanoparticles presenting alkyne groups via a continuous process using near-critical and supercritical water. J Supercrit Fluids 2013. [DOI: 10.1016/j.supflu.2013.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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21
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Collins G, O'Dwyer C, Morris M, Holmes JD. Palladium-catalyzed coupling reactions for the functionalization of Si surfaces: superior stability of alkenyl monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:11950-11958. [PMID: 23968278 DOI: 10.1021/la402480f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Palladium-catalyzed Suzuki, Heck, and Sonogashira coupling reactions were studied as reaction protocols for organic modification of Si surfaces. These synthetically useful protocols allow for surface modification of alkene, alkyne, and halide terminated surfaces. Surface oxidation and metal contamination were assessed by X-ray photoelectron spectroscopy. The nature of the primary passivation layer was an important factor in the oxidation resistance of the Si surface during the secondary functionalization. Specifically, the use of alkynes as the primary functionalization layer gave superior stability compared to alkene analogues. The ability to utilize Pd-catalyzed coupling chemistries on Si surfaces opens great versatility for potential molecular and nanoscale electronics and sensing/biosensing applications.
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Affiliation(s)
- Gillian Collins
- Department of Chemistry and the Tyndall National Institute, University College Cork , Cork, Ireland
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22
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Bhairamadgi NS, Gangarapu S, Caipa Campos MA, Paulusse JMJ, van Rijn CJM, Zuilhof H. Efficient functionalization of oxide-free silicon(111) surfaces: thiol-yne versus thiol-ene click chemistry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4535-42. [PMID: 23528051 DOI: 10.1021/la400007y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Thiol-yne click (TYC) chemistry was utilized as a copper-free click reaction for the modification of alkyne-terminated monolayers on oxide-free Si(111) surfaces, and the results were compared with the analogous thiol-ene click (TEC) chemistry. A wide range of thiols such as 9-fluorenylmethoxy-carbonyl cysteine, thio-β-d-glucose tetraacetate, thioacetic acid, thioglycerol, thioglycolic acid, and 1H,1H,2H,2H-perfluorodecanethiol was immobilized using TYC under photochemical conditions, and all modified surfaces were characterized by static water contact angle measurements, X-ray photoelectron spectroscopy (including a simulation thereof by density functional calculations), and infrared absorption reflection spectroscopy. Surface-bound TYC proceeds with an efficiency of up to 1.5 thiols per alkyne group. This high surface coverage proceeds without oxidizing the Si surface. TYC yielded consistently higher surface coverages than TEC, due to double addition of thiols to alkyne-terminated monolayers. This also allows for the sequential and highly efficient attachment of two different thiols onto an alkyne-terminated monolayer.
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Affiliation(s)
- Nagendra S Bhairamadgi
- Laboratory of Organic Chemistry, Wageningen University and Research Center, Dreijenplein 8, 6703 HB, Wageningen, The Netherlands
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23
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Ciampi S, James M, Choudhury MH, Darwish NA, Gooding JJ. The detailed characterization of electrochemically switchable molecular assemblies on silicon electrodes. Phys Chem Chem Phys 2013; 15:9879-90. [DOI: 10.1039/c3cp50355k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Eisenblaetter J, Bruns M, Fehrenbacher U, Barner L, Barner-Kowollik C. Synthesis of polymers with phosphorus containing side chains via modular conjugation. Polym Chem 2013. [DOI: 10.1039/c3py00103b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Manova RK, Pujari SP, Weijers CAGM, Zuilhof H, van Beek TA. Copper-free click biofunctionalization of silicon nitride surfaces via strain-promoted alkyne-azide cycloaddition reactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:8651-63. [PMID: 22642374 DOI: 10.1021/la300921e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Cu-free "click" chemistry is explored on silicon nitride (Si(3)N(4)) surfaces as an effective way for oriented immobilization of biomolecules. An ω-unsaturated ester was grafted onto Si(3)N(4) using UV irradiation. Hydrolysis followed by carbodiimide-mediated activation yielded surface-bound active succinimidyl and pentafluorophenyl ester groups. These reactive surfaces were employed for the attachment of bicyclononyne with an amine spacer, which subsequently enabled room temperature strain-promoted azide-alkyne cycloaddition (SPAAC). This stepwise approach was characterized by means of static water contact angle, X-ray photoelectron spectroscopy, and fluorescence microscopy. The surface-bound SPAAC reaction was studied with both a fluorine-tagged azide and an azide-linked lactose, yielding hydrophobic and bioactive surfaces for which the presence of trace amounts of Cu ions would have been problematic. Additionally, patterning of the Si(3)N(4) surface using this metal-free click reaction with a fluorescent azide is shown. These results demonstrate the ability of the SPAAC as a generic tool for anchoring complex molecules onto a surface under extremely mild, namely ambient and metal-free, conditions in a clean and relatively fast manner.
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Affiliation(s)
- Radostina K Manova
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands
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26
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Miyata T, Kawamura A, Meotoiwa T, Matsumoto M, Uragami T. Synthesis of novel nucleobase-terminated organosilane and its self-assembly on a substrate. Polym J 2012. [DOI: 10.1038/pj.2012.41] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Ciampi S, Guan B, Darwish NA, Zhu Y, Reece PJ, Justin Gooding J. A multimodal optical and electrochemical device for monitoring surface reactions: redox active surfaces in porous silicon Rugate filters. Phys Chem Chem Phys 2012; 14:16433-9. [DOI: 10.1039/c2cp43461j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Ciampi S, James M, Le Saux G, Gaus K, Justin Gooding J. Electrochemical “Switching” of Si(100) Modular Assemblies. J Am Chem Soc 2011; 134:844-7. [DOI: 10.1021/ja210048x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Simone Ciampi
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052,
Australia
| | - Michael James
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052,
Australia
- Bragg Institute, Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Guillaume Le Saux
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052,
Australia
| | - Katharina Gaus
- Centre for Vascular Research, The University of New South Wales, Sydney, NSW 2052,
Australia
| | - J. Justin Gooding
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052,
Australia
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29
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James M, Ciampi S, Darwish TA, Hanley TL, Sylvester SO, Gooding JJ. Nanoscale water condensation on click-functionalized self-assembled monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10753-10762. [PMID: 21780835 DOI: 10.1021/la202359c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have examined the nanoscale adsorption of molecular water under ambient conditions onto a series of well-characterized functionalized surfaces produced by Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC or "click") reactions on alkyne-terminated self-assembled monolayers on silicon. Water contact angle (CA) measurements reveal a range of macroscopic hydrophilicity that does not correlate with the tendency of these surfaces to adsorb water at the molecular level. X-ray reflectometry has been used to follow the kinetics of water adsorption on these "click"-functionalized surfaces, and also shows that dense continuous molecular water layers are formed over 30 h. For example, a highly hydrophilic surface, functionalized by an oligo(ethylene glycol) moiety (with a CA = 34°) showed 2.9 Å of adsorbed water after 30 h, while the almost hydrophobic underlying alkyne-terminated monolayer (CA = 84°) showed 5.6 Å of adsorbed water over the same period. While this study highlights the capacity of X-ray reflectometry to study the structure of adsorbed water on these surfaces, it should also serve as a warning for those intending to characterize self-assembled monolayers and functionalized surfaces to avoid contamination by even trace amounts of water vapor. Moreover, contact angle measurements alone cannot be relied upon to predict the likely degree of moisture uptake on such surfaces.
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Affiliation(s)
- Michael James
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC NSW 2232, Australia.
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30
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Ciampi S, James M, Darwish N, Luais E, Guan B, Harper JB, Gooding JJ. Oxidative acetylenic coupling reactions as a surface chemistry tool. Phys Chem Chem Phys 2011; 13:15624-32. [DOI: 10.1039/c1cp21450k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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